Within a power system, it is important to monitor line conditions, disturbances, faults etc. . . . Devices are integrated with such electrical power grids to monitor, control meter, communicate and perform a variety of other functions. For example, power line communication repeaters are used in some rural areas to transmit information from an automatic metering infrastructure (AMI). In general, the problem is in keeping electronic circuits, especially communication circuitry, operating while deployed within AC powered utility grid systems. Whatever power is provided to these devices must be able to supply adequate power for circuitry and ancillary communication equipment.
These devices and sensors (and their communications equipment) require power to operate. Low power sensors can rely upon high capacity batteries for years. However, to keep the sensor size and cost to a minimal, it is desired that the energy needs of the sensors and devices be met by miniature inexpensive batteries (for example coin cell batteries). These batteries will require frequent charging. Other powering means have involved solar cells and/or power transformers.
Generally all of these currently available means are less than ideal, are unreliable and are expensive. Batteries have limited power ability and the provision of ongoing power is always an issue. Solar power can assist in power regeneration but external factors such as day length, geography and weather can impact their usefulness. Power transformers are a solution but are prohibitively expensive and are over-kill i.e. they provide more power than is needed for the sensors and devices on the power grid. So, with all of these solutions either not enough or too much power is created.
A more recently explored solution is the use of devices to harvest energy directly from the current carrying conductor in a power system. The issue: it is not possible to input AC power into the devices, and DC power is not available in these environments. Researchers working in the field of energy harvesting are exploiting the principle of electromagnetic (EM) induction. More recently, Bhuiyan et al. investigated the use of an energy coupler by which wireless sensors can harvest power from a current carrying conductor.
Power line harvesting, using all currently available technologies, suffer from at least two major drawbacks: 1) lack of means to manage and control and provide consistent power to devices, given that AC power lines do not deliver a consistent amount of power in any electrical distribution system and 2) means to manage the charging and discharging of energy storage devices, fed the AC harvested power.
It is an object of the present invention to obviate or mitigate all or some the above disadvantages.